Cabinets which are assembled of metal side wall elements connected together with corner connecting rails are known, see for example U.S. Pat. No. 4,621,897, to which European Patent EP 0 133 605 corresponds. The connecting rails are slid into longitudinal grooves shaped or formed in the side wall or back elements.
For many applications, it is desirable to provide lightweight material, such as plastic. Foamed plastic is particularly suitable and can easily be made to have decorative aspects. This material, however, is soft and requires protection.